用于 NFC 的程序化意图过滤器

发布于 2024-11-09 18:58:25 字数 1592 浏览 0 评论 0原文

编辑：我找到了解决方案，请参见下文

我在 StackOverFlow 上的第一篇文章。然而，我已经阅读有关这个问题一段时间了，但没有有效的解决方案。

我想做的是注册以下意图： android.nfc.action.TAG_DISCOVERED

我在代码中执行以下操作：

    IntentFilter filter = new IntentFilter();
    filter.addAction("android.nfc.action.TAG_DISCOVERED");
    filter.addCategory("android.intent.category.DEFAULT");
    Log.d(TAG, "Created the new filter");
    reciever = new NFCBroadcastReciever(this);
    Log.d(TAG, "Created the new Broadcast Reciever");
    this.registerReceiver(reciever, filter);
    Log.d(TAG, "Registered new reciever");

BroadCastReciever 定义如下：

public class NFCBroadcastReciever extends BroadcastReceiver {

private Screen screen;
public static String TAG = "NFCBroadcastReciever";

NFCBroadcastReciever(Screen _screen){
    screen = _screen;
}

@Override
public void onReceive(Context context, Intent intent) {

    String action = intent.getAction();
    Log.d(TAG, "Action recieved: "+action);
    if(action != null && NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)){
        paymentScreen.onNewIntent(intent);
    }
}

}

但是我得到一个例外，该意图是从标签读取触发没有相应的活动。我希望能够仅在应用程序中的某个时刻开始监听 NFC 事件。

预先感谢您的帮助。

我实际上找到了问题的解决方案，关键是让 NFC 事件仅在特定活动处于活动状态时发生，而不是在其他活动运行时发生。 Android SDK 中的示例对此进行了解释： http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/nfc/ForegroundDispatch.html

原文

EDIT: I found the solution, see below

My first post on StackOverFlow. However I have been reading about this problem for a while without a solution that works.

What I would like to do is register the following Intent: android.nfc.action.TAG_DISCOVERED

I am doing the following in my Code:

    IntentFilter filter = new IntentFilter();
    filter.addAction("android.nfc.action.TAG_DISCOVERED");
    filter.addCategory("android.intent.category.DEFAULT");
    Log.d(TAG, "Created the new filter");
    reciever = new NFCBroadcastReciever(this);
    Log.d(TAG, "Created the new Broadcast Reciever");
    this.registerReceiver(reciever, filter);
    Log.d(TAG, "Registered new reciever");

The BroadCastReciever is defined as follows:

public class NFCBroadcastReciever extends BroadcastReceiver {

private Screen screen;
public static String TAG = "NFCBroadcastReciever";

NFCBroadcastReciever(Screen _screen){
    screen = _screen;
}

@Override
public void onReceive(Context context, Intent intent) {

    String action = intent.getAction();
    Log.d(TAG, "Action recieved: "+action);
    if(action != null && NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)){
        paymentScreen.onNewIntent(intent);
    }
}

}

However I get an exception that the intent being fired from a tag read has no corresponding Activity. I would like to be able to only start listening for NFC events at a certain point in my application.

Thanks in advance for your help.

I found the solution to the problem actually, the key to getting NFC events to occur only on a specific activity while it is active and not when other activities are running. The sample in the Android SDK explains it: http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/nfc/ForegroundDispatch.html

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